A storm out of the Gulf of Alaska will drop into Southern California late Wednesday, bringing lots of cold air and as much as six inches of snow to the San Diego County mountains, says the National Weather Service. The snow will begin on Wednesday night, initially falling at the 5,000 foot level. But flakes will drop as low as 2,000 feet by Thursday night. Temperatures across the eastern half of the county will drop into the 20s and 30s, and winds will sharply gust through canyons and foothills.

The storm also could drop one-tenth to one-quarter of an inch or rain west of the mountains, and the system will usher in a prolonged period of cold weather. Forecasters say a trough coming in behind the main storm could drop temperatures into the 30s on Friday and Saturday night, and into the teens and 20s in some areas of East County.

"It depends on what happens with the winds," said Brandt Maxwell, a weather service forecaster. "If the winds stay light, it will get really cold all the way to the coast."